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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

GLACIERS OF UNAKWTK INLET AND COLLEGE FIORD         311
(174 feet) northwest of Coghill River, and by a gradual shallowing of the water from that point to Port Wells.
As has been stated in previous discussions of the 1910 soundings, we are in doubt where to infer submerged moraines and where uneroded reefs, developed in connection with the basining of the fiord bottom by glacial erosion. The basin whose deepest point (804 feet) is opposite Wellesley Glacier seems to us probably to be a rock basin of glacial erosion. Its bottom lies 630 feet lower than the swell at its lower end, and 462 feet lower than the swell at its upper end. An apparently adequate explanation of excessive erosion here would be the more rapid motion of the ice when the expanded Harvard Glacier received Yale and the cascading glaciers as tributaries. Moreover, in this upper part of the fiord there may have been repeated ice advances, with consequent periods of glacial erosion, while the lower part of the fiord was not scoured so frequently, if indeed it was occupied by an advancing glacier more than once.
An alternate explanation of the relative shallowness in the part of the fiord south of Cog-hill River (Fig. 43) would be that it was originally more deeply eroded, but has been filled by glacial deposits, including not only deposits from the retreating glaciers of upper College Fiord, but also by stream-borne deposits from the A mti erst, Crescent, Williams
6 miles
FlG. 48,    StTBMAEINB CONTOURS OF COLLEGE FlORD.
Outline of coast and glaciers after Grant and Higgins.